1. Field of the Invention
The present invention relates to a multipurpose power supply suitable for power switch driver applications, and in particular to a power switch driver power supply circuit that is capable of being used with multiple variants of power switch driver circuits.
2. Description of the Related Art
Power electronics devices, such as DC-to-DC converters and switched mode power supplies, make use of high power transistors in order to provide a stable output voltage at a predetermined value from a given input power supply, and the transistors are continually switched on and off to regulate the output voltage. They have important applications in switching high currents in uninterruptible power supplies, motor drives, and solar inverters, and must therefore meet stringent constraints and requirements imposed upon the output voltage they produce. For example, it may not be acceptable for the output voltage to deviate from a nominal value by more than a predetermined tolerance.
Power switch driver circuits are used to control the high power transistors in power electronics devices. The power switch driver circuit provides the electronics necessary to operate (that is, to switch on and off) the high power transistors as is appropriate given the input voltage to which the power electronics device is connected, and the voltage that is fed back from its output. By adjusting the time for which the transistors are switched on and off, the voltage output by the power converter can be regulated.
Several types of high power transistors are known, for example, the Isolated Gate Bipolar Transistor (IGBT), the Silicon Carbide (SIC) transistor, and the Metal Oxide Field Effect Transistor (MOSFET). Therefore several variants of power electronics devices are in use, each employing a particular type of high power transistor.
Typically, each type of high power transistor requires connection to supply a pair of voltage rails with a potential difference between them. In the commonly recognized industry standard, Isolated Gate Bipolar Transistors require connection to rails held at +15 V and −10 V; Silicon Carbide transistors require connection to rails held at +20 V and −5 V; and Metal Oxide Field Effect Transistors require connection to rails held at +15 V and −5 V.
For correct functioning of the power electronics devices, it is therefore necessary to provide their power switch driving circuits with a power supply that is suited to the particular type of transistors used within the device, and that is capable of outputting voltages such that a suitable potential difference is maintained between the voltage rails.
The inventors of the present invention appreciated that it is desirable to provide a single power supply for use with power electronics applications requiring a variety of input voltages.